This invention relates to dampening the vibrations associated with the use of wire rope in industrial applications. More particularly, this invention relates to apparatus for reducing both fatigue and corrosion of wire rope terminations.
The term wire rope is generally understood to comprise a symmetrically arranged and helically twisted assembly of strands. A strand, in turn, is a symmetrically arranged and helically twisted assembly of individual wires. For simplicity, the term wire rope as used herein will include strand, as well.
Wire rope is designed and constructed to transmit forces longitudinally along its axis. It must be able to withstand destructive forces, such as tensile loading, bending fatigue, lateral crushing, abrasive wear, and corrosion, which act upon it during service. This invention is primarily concerned with bending fatigue and corrosion.
While wire rope is recognized in industry as a widely applicable structural member possessing high-strength and flexibility, it is also recognized that it is only as strong as its weakest link. this weakest link is often the area in the vicinity of the fittings. Fittings, or terminations as they are known in the art, are accessories used as attachments for wire rope. The stresses and strains to which wire rope is subjected are generally concentrated at such fittings.
Devices such as flared metal dampener clamps, have been used in an attempt to decrease the vibrations and thereby reduce the fatigue stresses in the wire rope at the terminations. However, such clamps do little more than transfer the fatigue point from one point in the termination to another equally vulnerable point, with little improvement in fatigue resistance.
Corrosion, another of the destructive forces, can occur as a result of the exposure of wire rope to moisture, acids, alkali, and the like, [either in the atmosphere or in hydrospace]. In oceanographic applications, wire rope is particularly susceptible to destruction by corrosion. In fact, experience has shown that because of the environment of the ocean, the effect of corrosion and fatigue operating together is greater than the effect of the sum of the effect of each. Prior art dampener clamps, have been found to be essentially ineffective in preventing either corrosion or fatigue in hydrospace.